<Insert Picture Here> Scale your PHP Application to Tens of Thousands of Connections

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3 <Insert Picture Here> Scale your PHP Application to Tens of Thousands of Connections Srinath Krishnaswamy Director, Data Access Development, Oracle Corp. Luxi Chidambaran Consulting Member of Technical Staff, Oracle Corp.

4 The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle s products remains at the sole discretion of Oracle.

5 Overview Motivation Oracle Database Resident Connection Pooling Using Oracle Database Resident Connection Pooling with PHP Availability Enhancements Result Caches Database Resident Connection Pool Demonstration

6 When should any thing be Pooled? When something is expensive to create When something is expensive to tear down! When something is expensive to maintain When you do not need the thing all the time Database Connections satisfy all of the above criteria

7 PHP users have asked for Database Connection Pooling Middle tier expected to scale horizontally Add more apache processes per box Add more boxes apache single threaded for PHP usage Client side connection pooling not possible apache process can repeatedly connect/disconnect apache process can hold onto private connection Results in inefficient use of the database resources

8 Persistent vs Non Persistent Use Non Persistent Connections? High connect times Unnecessary connect/disconnect CPU load Use Persistent Connections? Too many connections hanging around Too much memory Majority not doing work

9 Oracle Database Resident Connection Pool Pools Oracle Dedicated Servers Shares connection pool across apache processes Shares connection pool across middle tier instances Co-exists in all server configurations Dedicated Servers, Shared Servers, RAC

10 PHP and Connection Pooling No Connection Pooling 11G Server Side Connection Pooling

11 Basic Functionality Pooling is optionally enabled by DBA on server Min, Max, Timeout etc. for Pool Client connect string: hostname/service:pooled (SERVER=POOLED) Client directed to Server Side Pool Pooled Server locked when connection requested by client Pooled Server released back to pool when client releases connection

12 Concepts Clients authenticated as the same database user can share connections in pool CONNECTION_CLASS Allows for logical sub pools for a given user Allows clients to identify the type of connection required Clients with different connection classes do not share Clients with same user.connection_class share connections

13 Server Side/DBA View Default Connection Pool SYS_DEFAULT_CONNECTION_POOL dbms_connection_pool.start_pool() dbms_connection_pool.stop_pool() Configure Pool based on Available Resources dbms_connection_pool.configure_pool(min=>10, max=>300); Monitor Pool DBA views available V$CPOOL_STATS V$CPOOL_CC_INFO V$CPOOL_CC_STATS

14 Using Server Side Pooling with PHP Enhanced oci8 extension Code Compatible: No Application Code Changes Supports Installed base of existing applications Version Compatible: Application works as is with Existing Oracle databases (No Pooling) Database with Pooling disabled Database with Pooling enabled Extremely simple to turn on Pooling Deployment Decision

15 Apache/PHP Administrator View Download Beta OCI from PECL Talk to DBA and enable pool on Oracle Database Enable Pooling across Apache Instances Identify Apache instances that constitute an application Set :POOLED or (SERVER=POOLED) in connect string Set oci8.connection_class = <your_string> in php.ini on all apache instances that can share connections

16 Same APIs Transparently Pool oci_pconnect() Re-Uses Pooled Server process from pool Re-Uses Pooled Server session Very fast binding to an existing connection from pool oci_connect/oci_new_connect() Re-Uses Pooled Server process from pool The session is recreated Faster new connections! oci_close() Releases connection back to pool

17 Best Practices Do your homework Identify all apache instances serving an application Ensure clones doing identical work use the same connection_class setting Release connections early Do not hold on to a pooled connection when not necessary Do not wait until script end to implicitly close connection Try not to interleave other work (e.g static content) with database calls, when holding connection Do all non database work after oci_close()

18 Database Resident Connection Pool Performance Throughput & CPU usage in DRCP Throughput % and CPU% Throughput % Total CPU usage (%) Number of Connections

19 Database Resident Connection Pool Memory Utilization Memory Utilization in DRCP Memory Used (Mb) Number of Connections Connection Memory DB Instance Memory

20 Availability Enhancements <Insert Picture Here>

21 Motivating Problem The Consequences of Failure Perceived application hang Resort to TCP_TIMEOUT Current SQL statement appears to hang Application errors Application may get persistent connections to a dead node Attempted call will fail

22 Fast Application Notification Detect failure at server and client is notified OCI breaks blocking connections Cleans up idle dead connections Application can resume operations more quickly by retrying current transaction To enable FAN oci8.events=on enable FAN on database using DBMS_SERVICE facility

23 Solution Overview Stages Fatal Error Active FAILURE Request Idle Inst1 HM Retry Browser App Server Notification HM Inst2

24 Result Caches <Insert Picture Here>

25 SQL Query Result Cache Caches results of queries, query blocks, or pl/sql function calls Results cached in SGA Sharable between sessions, persist after initiating cursor closed Read consistency is enforced DML/DDL against dependent database objects invalidates cache Bind variables parameterize cached result with variable values join result query is 1 executes cached cached Group result by join Table 4 join query 2 uses cached result transparently Group by Table 1 join Table 2 Table 3 join Table 5 Table 5

26 SQL Query Result Cache Enabling /*+ RESULT_CACHE */ hint in queries result_cache_mode initialization parameter MANUAL, queries need hints to populate cache and lookup FORCE, queries will use cache without hint result_cache_max_size initialization parameter default max size chosen based on total memory available to SGA 0 disables result cache

27 OCI Client Query Result Cache like cache fusion between server and client Application Server Consistent Caching Database Caches SQL query results on client Targeted at repetitive queries against read-mostly, readonly data

28 Benefits Easy to Use Cache Frees application developers from building a per-process result cache shared by all sessions that is consistent. Extends server-side query caching to client side memory leverages cheaper client-side memory each application has its working set cached locally Ensures better performance by eliminating round trips to the server Improves server scalability by saving server resources Transparently does cache management memory management, concurrent access of result-sets, etc Transparently maintains cache consistency with server side changes Consistency mechanism works with RAC

29 Enabling Works with OCI-based drivers Including PHP, JDBC-OCI, OCCI, ODP.Net, Pro*C/C++, Pro*COBOL ODBC Client cache settings Server: CLIENT_RESULT_CACHE_SIZE (default 0, cache disabled) Client (set in sqlnet.ora): OCI_RESULT_CACHE_MAX_SIZE (optional) over-rides server cache size /*+ RESULT_CACHE */ hint in queries

30 OCI Client Query Result Cache Performance Results Nile benchmark to test Client Result Cache Simulates online bookstore Tested with 3000 users Results Up to 6.5 times less server CPU usage 15-22% response time improvement 7% improvement in mid-tier CPU usage S291617: Caching In on the Oracle Database 11g Query Result Cache in the Application Tier; Tuesday 11/13 12:15 PM - 1:15 PM Hilton Fransiscan Room C

31 Resources PHP Developer Center on OTN Oracle 11g DRCP White Paper pdf PHP OCI8 extension Beta from PECL

32 Demonstration of Database Resident Connection Pool

33 The preceding is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle s products remains at the sole discretion of Oracle.